Fix OpenGL underlink, man dir, and skip installing in $HOME.
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -111,5 +111,6 @@
 # Check for OpenGL and GLU
 #
-pkg_check_modules (OPENGL glu)
+set(OpenGL_GL_PREFERENCE GLVND)
+find_package(OpenGL)
 if (NOT OPENGL_FOUND)
 	message(FATAL_ERROR "OpenGL/GLU devel library not installed.")
@@ -277,5 +278,5 @@
 # Install nighthawk in games section of man page tree (iaw "man man")
 #
-install(FILES man/nighthawk.6 DESTINATION man/man6)
+install(FILES man/nighthawk.6 DESTINATION share/man/man6)
 
 # From investigation work and a strong recommendation by GCB (aka wotnot),
@@ -287,5 +288,5 @@
 # risk that install will break on future distributions. JN, 08NOV20
 #
-if (UNIX AND NOT APPLE)
+if (0)
 	install(FILES ${CMAKE_BINARY_DIR}/nighthawk.desktop DESTINATION ${HOME_PATH}/Desktop)
 	install(CODE "execute_process(COMMAND chown ${USERNAME}.${USERNAME} ${HOME_PATH}/Desktop/nighthawk.desktop)")